NASA currently envisions three launches for the SLS (Space Launch System) using a Block I configuration
and consisting of an ICPS (Interim Cryogenic Propulsion Stage) for its upper stage. The basic Block I vehicle will be capable
of deploying at least 70 tonnes to LEO. However, by utilizing the ICPS as an upper stage that can accommodate 27 tonnes of propellant, the Block I configuration with an ICPS upper stage will be able to deploy at least 95
tonnes of payload to low Earth orbit.

A Block IB configuration with an EUS (Exploration Upper Stage) is expected to be introduced by 2024. The EUS will be able to accommodate 128 tonnes of LOX/LH2 propellant. And this will enable the Space Launch System to deploy up to 105 tonnes of payload to LEO. NASA currently plans to use the Block IB configuration to assemble the future Lunar Gateway at NRHO (Near Rectilinear Halo Orbit). The Lunar Gateway will serve as a bridge for Lunar and Martian operations, substantially reducing the delta v requirement to reach the orbits of the Moon and Mars.

NASA's Current Launch Sequence for the SLS

2020:

The SLS Block I launch vehicle will deploy an unmanned Orion spacecraft to a Distant Retrograde Orbit (DRO) before returning the capsule to the Earth. DRO is interesting because of its lack of station keeping requirement. Such a distant equatorial orbit of the Moon might make DRO a prime location for massive rotating artificial gravity habitats perhaps sometime in the second half of the 21st century. It might also be a good location for small asteroids imported into cis-lunar space for potential exploitation.

2022:

The second SLS Bloch I launch is scheduled to send a crewed Orion spacecraft around the Moon as an inaugural human occupied beyond LEO spaceflight for the SLS system.

2023:

The third scheduled SLS Block I launch will be used to deploy the Europa Clipper to Jupiter orbit in order to study the surface of its icy moon, Europa.

2024:

The first launch of the SLS Block IB is scheduled for 2024. It will consist of an Orion crew of four plus a ten tonne component of the Lunar Gateway which will be assembled at NRHO . This location will eventually give crewed vehicles weekly access to the lunar surface with as little as 12 hours of travel time to and from the surface of the Moon.

2026:

Four subsequent SLS Block IB flights will be required to completely assemble the Lunar Gateway by 2026.

One. Only one or two SLS launches are required to deploy the Lunar Gateway to NRHO-- not five SLS launches. Of course, the amount of mass that can be deployed to NRHO by the SLS is substantially reduced under the NASA scenario because of the joint launch of the Orion spacecraft and Service Module. This would be an unnecessary joy ride for NASA astronauts that would greatly inflate the cost of deploying the Gateway while also significantly delaying its full implementation.

Why spend more than two to five times as much as you have to deploy the Lunar Gateway when dollars for NASA's human spaceflight related programs are so hard to come by? Plus NASA needs more funding to help private companies develop lunar crew landing vehicles, space propellant depots, extraterrestrial habitats, and interplanetary crew transport spacecraft.

Two. Under NASA's current scenario, the Lunar Gateway wouldn't even start to be assembled until 2024 with a completion date around 2026. Again, a totally unnecessary delay in deployment.

An SLS Block I with an ICPS upper stage could probably deploy a complete SLS derived Deep Space Habitat to NRHO as early as 2022 that weighs about 20 tonnes-- without consumables. Food and water could subsequently be launched to the Gateway by commercial launch vehicles.

An SLS Block IB, would be able to deploy SLS derived Deep Space Habitat concepts weighing 22 tonnes for 353 cubic
meters of habitable pressurized volume and 28 tonnes for 519 cubic
meters of habitable pressurized volume with a single launch in 2024. That would still be two years earlier than NASA's current Lunar Gateway completion plans.

However, a large private commercial upper stage is currently being developed by the ULA (United Launch Alliance) that will be used to deploy payloads for the Air Force (Space Force?). And the ULA's Centaur V could be certified for military payloads in 2021 and ready for utilization in 2022.

If the SLS was used to deploy a large commercial upper stage (Centaur V) to LEO, NASA could deploy a 28 tonne SLS derived Deep Space Habitat to NRHO with just two launches. Assuming a maximum dry weight of no more than seven tonnes for the Centaur V, an SLS Block one launch could deploy the Centaur V to orbit with at least 63 tonnes of propellant. An SLS Block I with an ICPS upper stage could deploy the Centaur V with
68 tonnes of propellant to LEO plus 20 tonnes of additional payload for, perhaps, another ICPS with at least 16 tonnes of additional
propellant.

After docking with an SLS payload deployed to LEO by a previous SLS launch, the Centaur V should be easily capable of transporting more than 30 tonnes of payload to NRHO.

However, the preceding SLS Block I launch would be able to deploy up to 70 tonnes of payload to LEO. So you could actually deploy two 28 tonne habitats to LEO (just 56 tonnes) with one destined for NRHO after the next SLS upper stage launch-- while the other 28 tonne habitat remains at LEO as a potential replacement for the ISS.

Replacing the ISS with a new space station would possibly save NASA up to $4 billion a year!

An SLS derived LEO habitat wouldn't be a space laboratory, it would simply be a habitat used for NASA and Space Force astronaut training and for the training of astronauts from foreign space agencies. It could also be a used as a destination for wealthy space tourist and space entrepreneurs. Small commercial launched space laboratories could be co-orbited near the LEO habitat while lab specialist use the SLS derived habitat as a hotel, visiting their floating laboratory only when necessary to add or retrieve materials.

Alternatively, NASA could deploy three 22 tonne SLS derived habitats to LEO with one destined for NRHO with the other two remaining at LEO. One could be used exclusively for NASA and the Space Force with the other being auctioned off to a private space company for space tourism or to accommodate the needs of foreign space agencies.

While the above scenario might delay the first crewed flight of the SLS until 2023 (just one year), it would actually give astronauts a place to go on their first SLS flight in 2023. Of course, NASA could still have a test flight of a crewed Orion in 2021 instead of 2022. NASA astronauts could use commercial crew vehicles to travel to LEO to inspect the Gateway habitat before its deployed to NRHO.

Three. There's no logical reason to waste an SLS launch for a flyby mission of Europa. The Europa Clipper can probably be deployed by commercial launch vehicles. However, an orbital mission to Europa is questionable since the moon Callisto would be much easier to access. Callisto is the only place in Jupiter space where human outpost could be set up for potential colonization. A human outpost on the surface of Callisto would make it substantially easier to explore Europa, Ganymede, and Io (all within Jupiter's deadly radiation belt) with robots remotely controlled from the surface of Callisto. A better near term use for a non human spaceflight related launch of the SLS would be the deployment of space telescopes with mirror diameters even larger than the James Webb.

The utilization of reusable vehicles for the human exploration, pioneering, and exploitation of the lunar surface is one of the primary reasons for having a Lunar Gateway at NRHO. Reusable spacecraft will, of course, require propellant depots.

Once the Lunar Gateway is deployed, co-orbiting propellant depots can also be deployed to NRHO by private commercial launch companies. NASA breakthroughs in zero boil off (ZBO) liquid hydrogen storage should make it possible for commercial launch companies to deploy propellant tank derived LH2 (liquid hydrogen) and liquid oxygen (LOX) storage tanks to NRHO that don't leak any hydrogen or oxygen. More sophisticated technologies could allow the solar power production and liquefaction of hydrogen and oxygen from water in space which could substantially reduce launch complexity and cost for commercial launch companies.

With its Integrated Vehicle Fuel (IVF) technology, the ULA's ACES-68 successor to the Centaur V could be in operation as early as 2023 but is currently planned to go into operation within the 2024 to 2025 time frame. It now seems likely that the ULA will allow Lockheed Martin, one of its parent companies, to be first to develop IVF technology for its future reusable crewed lunar landing vehicles. In tandem (on either side of an orbiting payload) two such ACES vehicles could transport payloads exceeding 70 tonnes from LEO to NRHO or to Low Lunar Orbit. A single ACES 68 could deploy an equal amount of payload to Mars orbit from NRHO; so massive amounts of water or propellant deployed to NRHO could easily be later deployed to Mars orbit from NRHO.

If propellant depots are deployed at LEO and NRHO, the ACES-68 could replace the ICPS and the Service Module for the Orion space capsule. This would make the Orion a completely reusable vehicle for transporting astronauts between LEO and NRHO. So no longer would the Orion spacecraft have to be deployed by the SLS for deep space missions. The ULA's Vulcan spacecraft could deploy the reusable Orion/ACES to LEO, fueling the ACES 68 booster at a LEO propellant depot before heading for NRHO or Low Lunar Orbit.

So, in theory, astronauts could board a commercial launch vehicle (Falcon 9/Dragon, Atlas V/Centaur/CST-100, etc.) that transports them to LEO. The could then dock with an already propellant depot fueled Orion/ACES vehicle for transport to the Lunar Gateway or to Low Lunara Orbit. Again, no SLS launch would be required which means that the heavy lift vehicle could be more properly used to transport heavy payloads to LEO.

If NASA eventually uses commercial upper stages such as the Centaur V and the ACES 68 to transport large and heavy payloads initially transported to LEO by the SLS then the space agency could delay the deployment of the EUS and focus on developing a far more enhanced orbital transfer vehicle. An SLS derived EUS equipped with IVF and cryocooler technologies could make such a vehicle reusable. Such a vehicle could simply use the SLS core stage liquid oxygen tank as a liquid hydrogen tank while also deriving a smaller oxygen tank from the same technology.

Such a reusable vehicle could accommodate more than 345 tonnes of LOX/LH2 propellant. And it could be used to transport large habitats and their crews to the orbits of Mars, Venus, and to the NEO asteroids from NRHO. The performance of such a reusable interplanetary crew transport could also be greatly enhanced by coupling it with a twin transport or just a reusable ACES booster with 68 tonnes of propellant. Propellant depots in Mars orbit would be required for the the return journey to Earth. But, again, the water or propellant could be routinely transported to Mars orbit from water or propellant transported from the lunar surface to NRHO. Eventually, however, propellant depots in Mars orbit could be routinely supplied with water or propellant extracted from the regolith of the martian moons, Deimos and Phobos. And it might even be economical to transport liquid hydrogen from the surface of Mars from reusable spacecraft to orbiting depots to be used with liquid oxygen extracted from the martian moons for propellant.

SLS 6: SLS Block I with ICPS upper stage launches a Centaur V with an 8 meter class space telescope to ESL2 (Earth-Sun Lagrange Point 2). The new space telescope will have an 8 meter plus monolithic primary mirror housed within a 12 meter in diameter payload fairing. And it will join the with join the 6.5 meter in diameter James Webb telescope at ESL2. The diameter for the mirror for the Hubble Telescope was 2.4 meters. The development of such a enormous fairing size for the SLS will greatly enhance the launch vehicles unique ability to accommodate exceptionally large payloads. NASA needs to stop entertaining smaller payload shrouds for the SLS that could nullify its advantage over other launch systems.

(Commercial launch companies begin the continuous deployment of tanks of LOX and LH2 to depot clusters at LEO and NRHO)

{NASA begins using new RS-28 engines for the SLS core vehicle. Hopefully, some meager funding to develop an SLS-B (the SLS without Solid Rocket Boosters) with a commercial Centaur V or ACES upper stage and a commercial CST-100, Dream Chaser, Dragon, or maybe even an Orion as the crew capsule. This would allow more frequent use of the SLS core stage and its RS-25 engines which should help to substantially reduce the overall cost of SLS launches.}

2024:

SLS 7: SLS Block I launches two reusable Lockheed Martin Lunar Crew Landing Vehicle (LCLV) equipped with advanced IVF and cryocooler technology. One LCLV will be launched with enough fuel to self deploy itself to the Lunar Gateway at NRHO. The LCLV already fueled with LH2, will utilize a LEO orbiting LOX depot in order to fuel itself for self deployment to NRHO.

Both Lunar Crew Landing Vehicles will be fueled and tested (unmanned) at NRHO with each traveling to opposite lunar poles to deploy mobile robots to the surface via their lift elevators. Some of the mobile robots will collect regolith samples for return to the Lunar Gateway and eventually to Earth. A few weeks later, one LCLV will be deployed to the surface of the far side of the Moon to collect regolith more lunar regolith samples while proving the vehicle's reusability.

{First NASA /ULA funded unmanned test of a reusable Orion/ACES to NRHO followed by the first crewed Orion/ACES to the Lunar Gateway at NRHO. The reusable vehicle will be launched into orbit by the ULA Vulcan rocket. The success of reusable Orion/ACES spacecraft and reusable Lockheed Martin Lunar Landing Vehicle (used for crew transport between LEO and NRHO) should end the necessity of using the SLS to deploy astronauts to NRHO Gateway}

SLS 8: Last crewed SLS Block I launch of Orion/SM/ICPS to Lunar Gateway at NRHO.

After the six member crew arrives at NRHO, four astronauts will climb aboard one of the Lunar Crew Landing Vehicles to travel to one of the lunar poles (The first Americans to land on the lunar surface since 1972). If the crew on the lunar surface should have some serious difficulties attempting to return to the Lunar Gateway, the remain astronauts at NRHO will use the second LCLV to rescue the astronauts from the lunar surface, returning them safely to the Lunar Gateway.

So under this SLS launch scenario (before the end of 2024), NASA would have a new simpler and cheaper (and possibly money making) space station at LEO, a new Lunar Gateway at NRHO, plus American astronauts and hopefully, guest astronauts from foreign space agencies, routinely traveling to and from the lunar surface from the Lunar Gateway on private commercial landing vehicles.

Wednesday, November 28, 2018

California's forest, woodland areas, and its nearby residents are the latest victims of climate change as the world's fossil fuel dominated energy economy continues to increase greenhouse gasses in the Earth's atmosphere to dangerous levels.

The state of California has 33 million acres of forest land. Less than 400,000 of that acreage burned in California from 1980 to 1990. But just last year, 1.4 million acres burned in California. And so
far this year, 1.8 million acres of California land has burned.

Why?

California has grown 3 degrees warmer during the autumn seasons over the past
40 years while rainfall in the state has decreased by about one third during the same
period of time.

The
Federal government owns about 57% of the woodlands in California. Privately owned forest accounts for about 40% of California's woodland areas. But the State of California only owns about 3% of Califorinia's forest.

It is currently estimated that California's woodland areas have approximately 129 million dead trees. . Ironically, removing dead trees actually enables the spread of grasses and combustible weeds that make forest more likely to burn. Dry kindling, brush, bushes and twigs are the principal catalyst for the rapid spread of wildfires. So such vegetation also has to be safely managed.

Some of the worst forest fires in California have been caused by power lines. This has prompted some in the state to suggest burying power lines that transverse forested areas. But their are more than 176,000 miles of power lines in California. And putting power lines underground would cost ten times as much as stringing them on poles.

Controlled burning of woodland vegetation has long been a method for fire mitigation since before the arrival of Europeans in North America. But burning woodland vegetation would increase the amount of excess carbon dioxide put into the Earth's atmosphere, exacerbating the problem of rising temperatures that have helped to enhance the fire danger in California in the first place.

But there is an alternative solution that could make the mitigation of forest fires in California economically sustainable while also reducing California's dependence on fossil fuels. And such measures cold eventually lead California's energy production and use becoming completely carbon neutral. And all it would take would be for two legislative measures to pass within the State of California.

Its my view that the State government in California should pass legislation that:

1. Mandates that all utilities producing electricity within the State of California produce at least 5% of that electricity for their customers by using-- bio-methanol-- directly derived from the dead trees and potentially dangerous woodland biomass in California’s forest and wooded residential areas by the year 2025 and up to 10% by the year 2030

and

2. Requires all gasoline sold in California to contain at least 5%-- bio-gasoline-- synthesized from bio-methanol that is directly derived from the dead trees and potentially dangerous woodland vegetation in California's forest and wooded residential areas by the year 2025 and up to 10% by the year 2030.

Approximately 33% of the electricity produced in California is generated by natural gas power plants. About 53% of California's electric power is produced by carbon neutral renewable and nuclear power energy sources.

Gasoline can be blended with methanol up to 15% without any modifications to an automobile. But
energy companies have been
able to synthesize methanol directly into high octane gasoline since the 1970s. And this would allow any level of mixing with gasoline from petroleum. In theory, you could have gasoline that is 80% derived from bio-methanol and 10% from petroleum with the remaining 10% of the fuel being composed of ethanol. Such an automotive fuel would be-- 90% derived-- from renewable biomass, reducing the utilization of gasoline from oil by 90%.

Any increases in the cost of gasoline
containing bio-gasoline from bio-methanol could encourage Californians
to purchase more fuel efficient electric and plug-in-hybrid electric
vehicles. But a vehicle fuel mix of 10% ethanol (Federally mandated), 10% gasoline from bio-methanol, and 80% gasoline from petroleum could substantially reduce oil demand, possibly mitigating any additional cost related to a mandated use of 10% bio-gasoline.

Methanol could also be directly used in high fuel efficiency hybrid fuel cell vehicles. Using methanol directly in automobiles would, of course, be cheaper than converting methanol into gasoline. Bio-methanol derived from California's forest could also be used to
produce biodiesel.

There
is also a growing global interest in using methanol to power sea
vessels. Methanol powered ships would be cleaner and bio-methanol ships with no sulfur emissions and lower nitrogen oxide emissions relative to current marine vessels powered by fuels synthesized from petroleum. Marine methanol ferries are already operating between Sweden and Germany.

Legislation mandating the use of bio-methanol from California's forest should provide a strong economic incentive for energy
companies selling electricity and gasoline in California to hire forest
workers to aggressively harvest dead trees and other potentially
dangerous woodland vegetation from California forest and residential
woodland areas for conversion into methanol. This should substantially reduce the level of fire danger in California's woodland
areas while also reducing the amount of CO2 put into the atmosphere as the result of the reduction in forest fire and forest fire intensity.

Beyond the reduction in fire danger, hiring people to harvest potentially dangerous woodland biomass should have a positive economic impact for nearby residential communities. Converting at least 10% of the natural gas power plants in California for methanol utilization should also have some positive economic impact for communities near such energy producing facilities. And the deployment of pyrolysis and synthesis facilities designed to convert biomass into methanol within California should have positive economic impact for the entire state.

Notional Flying Whale airship (Credit: Flying Whales)

The enhanced harvesting of dead trees and potentially dangerous woodland vegetation from remote forest might also encourage energy companies within California to utilize the next generation of airship technology. And airships might also greatly enhance the ability of the State of California and the US Federal government to fight fires in California's forest.

Airships being developed by the French company, Flying Whales, are being designed to transport up to 60 tonnes of lumbar within forested areas. Such airship technology could obviously be of use in California for removing the hundreds of dead trees that currently exist in California forest.

Lockheed Martin, on the other hand, is developing an airship that could transporting payloads up to 20 tonnes in mass within a large cargo bay. Forest kindling, grass, bushes, twigs and other potentially dangerous vegetation could be removed from California forest by Lockheed Martin's airships.

Similar airship technology could also be used by the State and Federal government to fight forest fires, dousing woodland fires and residential areas near forest with tonnes of water routinely retrieved from nearby lakes. The Lockheed Martin airships could also be used to rescue residents and fire fighters that might be trapped by raging forest fires.

The aggressive utilization of airship technology in California could help California businesses to lead the US and the world in the new age of airships. And, in theory, such airships could be fueled with dimethyl ether, derived from methanol derived from California's forest my modifying the diesel engines to use dimethyl ether.

Lockheed Martin airship (Credit: Lockheed Martin)

The introduction of a methanol economy into California could also enhance the ability of the state to become-- completely carbon neutral by mid century. This, however, would require the production of hydrogen through renewable or nuclear resources-- or a combination of both. Hydrogen could be used to synthesize methanol from wasted CO2
from the pyrolysis of urban and rural biomass and
from the CO2 waste from the flu gasses of methanol electric power plants.

For
California to be completely carbon neutral, all of the natural gas
electric power plants in California would have to be converted into
methanol power plants. The gradual conversion of electric power
production from natural gas to renewable methanol would make California
carbon negative during the transition from fossil fuels to renewable biomass, with more CO2 being extracted from
the Earth's atmosphere than being returned to the atmosphere. However, once all fossil fuel power plants have been replaced by methanol power plants that recycle CO2 from methanol synthesis and flu gas, then electric energy production and consumption in California would be carbon neutral.

Synthesis of renewable methanol from biomass.

Hydrogen in California could be produced from large solar or nuclear facilities located near biomass pyrolysis plants and methanol electric power plants. Alternatively, such facilities located near California coastlines could liquefy the carbon dioxide, exporting the CO2 by tankers to remote ocean nuclear power or renewable (floating wind, solar, or OTEC) facilities in remote US territorial waters where methanol and other renewable synthetic fuels could be safely manufactured. The Exclusive Economic Zones (EEZ) surrounding remote island territories such as: Wake Island, Howland Island, Baker Island, Johnston Atoll, Jarvis Island, etc. could be regions where floating vessels could use carbon neutral energy sources to produce methanol, jet fuel, dimethyl ether, gasoline and diesel fuel far away from urban populations. Methanol could then be shipped by methanol powered tankers back to the California coastline to fuel its methanol electric power plants or for conversion into renewable gasoline.

But once the transition from fossil fuels is complete, California energy production and consumption would be carbon neutral. Eventually, California will have a shortage of bio-carbon resources for its energy economy which would require the extraction of additional CO2 directly from the atmosphere or from seawater or both.

Monday, October 22, 2018

At the 69th International Astronautical Congress held in Bremen, Germany this month, Lockheed Martin unveiled a new reusable lunar crew lander concept.

For simplicity, I'll designate the notional Lockheed Martin spacecraft discussed in this article as the R-LL (Reusable Lunar Lander). According to Lockheed Martin, the R-LL will have dry weight of 22 tonnes and be capable of storing up to 40 tonnes of LOX/LH2 propellant. The R-LL will have up to 5 km/s of delta-v capability.

Lockheed Martin argues that the R-LL should be capable of crewed round trip missions to any area of the lunar surface from NASA's future Deep Space Gateway (DSG) which is to be located at a Near Rectilinear Halo Orbit (NRHO). Such round trip missions, they argue, would also be capable of delivering up to one tone of payload to the lunar surface in addition to a crew of four individual astronauts.

While Lockheed Martin has been rather vague about the exact dimensions of
the
R-LL, they have indicated that it will consist of only two cryotanks and
will be derived from the Centaur upper stage family and its
descendants. They also suggest that the R-LL will have a diameter close to that of the future Orion spacecraft.

Since Lockheed Martin's Centaur V is
currently in development as the future upper stage for the ULA's future
5.4 meter in diameter Vulcan rocket, one might speculate that the diameter of the R-LL cryotanks might be the same as and is supposed to have the same 5.4 meter diameter as the Centaur V. Such large diameter liquid hydrogen and liquid oxygen tanks should be capable of easily accommodating the 40 tonnes of propellant required for the
R-LL. So deriving the lunar vehicle from the Centaur V cryotanks might be the simplest and cheapest path towards rapidly developing the R-LL.

Lockheed Martin's Notional Reusable Crewed Lunar Landing Vehicle

Propellant: 40 tonnes of LOX/LH2

Inert Weight: 22 tonnes

Engines: Four RL-10 derived engines

Maximum delta-v capability: 5.0 km/s

Maximum number of crew: Four

Additional cargo capability: one tonne of additional cargo
The R-LL would use four engines to provide engine out
capability. This would enhance crew safety during attempted landings in
case of a serious malfunction with one of its engines. So just two counter balancing engines could be used during a landing in case of single malfunction engine. Lockheed Martin
says that
engines for the R-LL would be derived from Aerojet Rocketdyne's
RL-10 family or
from Blue Origins restartable BE-3 engine. Aerojet Rocketdyne's RL-10
derived CECE engines would be capable of at least 50 restarts with a throttling range from 104 percent to just eight percent of thrust.

Departing
from the Deep Space Gateway, it would take approximately 12 hours for
the R-LL to reach any point on the lunar surface. Another
12 hours would be required for the R-LL to return to the gateway at
NRHO.

NRHO: (Near Rectilinear Halo Orbit):

Travel time to and from LEO:~5 days from LEO (3.95 km/s)

Station keeping: 5 m/s per year

Travel time to and from LLO:~ 12 hours to LLO (0.730 km/s)

Lockheed
Martin says that their notional lunar spacecraft would be capable of
accommodating a crew of four astronauts on the lunar surface for up to
two weeks. Such a lengthy stay would require at least four tonnes of
additional shielding mass to protect astronauts from the inherently deleterious
heavy nuclei component of cosmic radiation and from a major solar flare. So one would assume that
such enhanced radiation shielding would be part of the notional space vehicle's 22 tonnes
of inert mass.

Lockheed Martin has also suggest that
propellant depots could be co-orbited with the Deep Space Gateway so
that the R-LL can be refueled at NRHO.

The simplest
propellant depots would probably have to be utilized within a month after deployment to NRHO since approximately 3.81% of
its liquid hydrogen and 0.49% of its liquid oxygen would boil off within a months time. For the 40 tonne LOX/LH2 requirement for the R-LL, such propellant depots would probably have to NRHO by the SLS or the BFR.

More sophisticated propellant depots could be equipped with cryocoolers and solar arrays capable of re-liquefying fuel boil-off. Ullage gases from the boil-off of liquid hydrogen could be used to re-liquefy gaseous oxygen while 12 to 15 kWh of
electricity would be needed to liquefy one kilogram of gaseous hydrogen. The 5.7 tonnes of liquid hydrogen required for a lunar mission would lose more than 217 kilograms of LH2 per month (7.2 kilograms per day). But a 10 kWe
solar array deployed to NRHO capable of producing more than 240 kWh of electricity per day would
be capable of re-liquefying 16 to 20 kilograms of LH2 per day. The solar arrays for the Orion spacecraft will be capable of producing more than 11 kW of electric power. So it should be rather simple to deploy propellant depots already equipped with cryocoolers and and solar panels in order to prevent fuel boil-off.

Solar powered depots that simply re-liquefied its ullage gases and powered pumps for storing and transferring liquid fueles would only require the continuous delivery of liquid hydrogen and
liquid oxygen. Future Vulcan
Heavy/Centaur rocket could deliver 7.3 tonnes of liquid hydrogen or
oxygen to NRHO per launch. Monthly launches could deliver
more than 87 tonnes of propellant to depots located at NRHO per year, more than enough for two R-LL
missions to the lunar surface per year.

Notional propellant producing water depot (Credit: Lockheed Martin)

The most technologically complex propellant depots could use solar power to actually
produce liquid hydrogen and liquid oxygen directly from water. This
would require the addition of an electrolysis plant plus substantially
more solar power. A 375 KWE solar array proposed by Lockheed Martin
could produce 40 tonnes of liquid hydrogen and oxygen propellant at NRHO
per month. Such huge 375 KWE solar arrays would weigh less than four tonnes. And two such arrays could be directly delivered to NRHO with a single SLS launch. But much smaller commercial launch vehicles could deploy 300 KWe arrays to LEO
for later transport to NRHO by fueled upper stages deployed to LEO. 300 KWE
arrays at NRHO could produce 40 tonnes of propellant in five or six
weeks rather than just four weeks for the larger arrays.

Solar powered
propellant producing water depots would make it much simpler and safer
for commercial rockets to deliver fuel to NRHO since the payload would only be water. Propellant producing water depots at NRHO could
eventually be supplied with water from the lunar poles.

Of course, water
and propellant being produced on the lunar surface itself would
dramatically reduce the amount of propellant required for R-LL
departures from NRHO. Reusable tanker vehicles directly derived from the
R-LL could deliver more than 40 tonnes of lunar water to propellant
producing water depots at NRHO per flight. Just 12 round trips from
the lunar surface could deliver enough water to NRHO to manufacture
enough fuel for crewed missions to the orbits of Mars or Venus.

Lockheed
Martin envisions that astronauts would be deployed to the NRHO gateway
via the Orion and the Space Launch System. And then the would take the
R-LL to the lunar surface and back to the NRHO gateway. And then they
would take the Orion back to Earth.

However, propellant depots
deployed at LEO would make SLS crew launches of the Orion vehicle
obsolete. Refueling at LEO, the R-LL would have more than enough delta-v capability to transport crews from LEO to the NRHO gateway. And refueling at NRHO, the R-LL would, of course, be capable of returning crews from NRHO back to LEO. And even with 22 tonne of inert weight, a
5.4 meter in diameter R-LL could be launched to Leo aboard a
Vulcan/Centaur launch vehicle within a 6.4 meter in diameter payload
fairing.

So for trips to the lunar surface, astronauts would simply take a Commercial Crew
Launch vehicle (Falcon9/Dragon or Vulcan/Centaur/CST-100) to a
commercial space habitat at LEO where a propellant depot refueled R-LL
was already docked and ready to be boarded. The R-LL would leave LEO
with enough propellant to take its crew on a 5 day journey to the NRHO gateway
where another already depot fueled R-LL would already be docked. The
second R-LL would take the crew for a round trip to the lunar surface, 12 hours to reach the surface and 12 hours to return to astronauts to the Deep Space Gateway.
The astronauts would return to the gateway with the first R-LL already
fueled for their return to a commercial space station at LEO. The Crew
would than take a Dragon or CST-100 Starliner back to the Earth's
surface.

Such an architecture would, finally, allow the SLS to be used--exclusively-- as a super heavy lift cargo transport. Such payloads could include: large and spacious microgravity and artificial gravity habitats derived from SLS propellant tank technology, large water and propellant depots derived from SLS propellant tank technology, interplanetary spacecraft capable of accommodating at least 400 tonnes of propellant derived from SLS propellant tank technology for crewed missions to the orbits of Mars and Venus, 8 meter in diameter space telescopes exceeding the capability of the James Webb telescope, and large inflatable microgravity and surface habitats that could make it a lot more spacious and comfortable for future astronauts and tourist to live under artificial gravity conditions in space or on the hypogravity surfaces of the Moon and Mars.

Thursday, August 23, 2018

During a recent 10 day testing period, Aerojet Rocketdyne successfully hot-fired its new Space Shuttle Main Engine (SSME) derived rocket engine-- the AR-22. The Sacramento, California headquartered company successfully demonstrated that the AR-22 could be restarted every 24 hours for ten consecutive days. And this is a major step towards testing the new rocket engine's reusability in Boeing's future unmanned space plane-- the Phantom Express.

Boeing's first test flights of the Phantom Express are currently scheduled for 2021. But the final test of the reusable space plane will entail launching the Phantom Express ten times in just ten days while deploying payloads between 3000 to 5000 lbs (1.36 tonnes to 2.27 tonnes) to LEO with an expendable upper stage.

Launching the Phantom Express with a single rocket engine, the AR-22 will be designed to be utilized up to ten times before requiring refurbishment. And each AR-22 engine will have an ultimate lifetime of 55 missions before before being completely replaced by a brand new AR-22 engine. Boeing estimates the cost to launch a the Phantom Express to be less than $5 million. And Boeing plans to commercialize the
Phantom Express, offering the space plane to both US government and commercial customers.

Just seven AR-22 engines would have to be produced every year in order
for the Phantom Express to be continuously launched on a daily basis.

If the Phantom Express were used to transport a valuable commodity such as water to LEO then 13 to 22 tonnes of water could be launched into orbit in ten days for less than $50 million, more than 40 tonnes of water in a month, and for less than $500 million. Optimally, the most advanced version of NASA's Space Launch System is eventually supposed to be able to deploy up to 130 tonnes of payload to orbit for about $500 million per launch. But for less than $500 million, 100 hundred launches of the Phantom Express could deliver between 130 tonnes to 220 tonnes of water to LEO.

Total mass of a commodity that can be deployed to LEO via daily launch of a single Phantom Express space plane:

Daily - 1.36 to 2.27 tonnes

Monthly - 40.8 to 68.1 tonnes

Yearly - 496.4 to 828.6 tonnes

Water, of course, is an indispensable commodity for human survival on Earth. And water would be even more valuable for human commerce and survival in extraterrestrial environments. Aboard the ISS, water is used for drinking, washing, food preparation, and for the production of air through electrolysis. Water can also be used for growing fruits and vegetables, aquaculture, animal husbandry. Water can also be used for shielding astronauts from the extremely deleterious heavy nuclei component of cosmic radiation while also mitigating the effects of cosmic radiation in general and ions from major solar events (solar storms).

But electrolysis used to produce oxygen for air also produces hydrogen. And electricity can also be used to liquefy both oxygen and hydrogen for use as a propellant for reusable extraterrestrial vehicles. While the current SLS could deploy up to 90 tonnes to LEO, it can only
transport about 25 tonnes of cargo on a trans lunar injection
trajectory. But with the assistance of LEO orbiting propellant producing water depots, a reusable extraterrestrial vehicle such as the ULA's future LOX/LH2 fueled Integrated Vehicle Fluids (IVF) ACES-68 could transport more than 50 tonnes of payload on a trans lunar trajectory. And a notional IVF modified SLS Exploration Upper Stage (R-EUS) could be used to transport more than 100 tonnes of payload on a trans lunar trajectory.

The propellant producing water depots could be simply derived from
the propellant tanks of extraterrestrial vehicles with the edition of
radiation panels, water storage, electrolysis plants for splitting the
water into hydrogen and oxygen , and cryocoolers to liquefy the gaseous
hydrogen and oxygen. Such depots could also be equipped with IVF
thrusters for station keeping and with rocket engines to enable the
depot to self deploy practically anywhere within cis-lunar space and
even into orbit around Mars, Venus, Jupiter, and the asteroids in the
asteroid belt.

A depot derived from the ACES upper
stage could store up to 68 tonnes of LOX/LH2 propellant while an EUS
derived depot could store up to 128 tonnes of LOX/LH2 propellant. Reusable upper stage rockets that use liquid methane instead of hydrogen as fuel, could utilize the excess amount of oxygen (22%) produced at depots that can't be used by the limited amount of hydrogen produced.

The
large solar arrays needed to provide power for propellant producing
water depots in orbit could be deployed by commercial launch vehicles.
The ULA's future Vulcan spacecraft with its 5.4 meter in diameter
payload fairing could deploy a 300 MWe solar array to LEO with a single launch.
Two such solar arrays docked to each other could provide up to 600 MWe of power
within cis-lunar space. Orbiting at LEO, such depots should have access to ample sunlight for producing propellant 61% of the time. But at the
Earth-Moon Langrange points, such as NRO, solar energy would be
uninterrupted, allowing water depots to
produce liquid hydrogen and oxygen continuously as long as water is provided.

Reusable ACES or R-EUS derived orbital transfer vehicles could transport water from
LEO to other propellant producing water depots located at the Earth-Moon
Lagrange points. But once water is manufactured and exported from the Moon's low gravity well, exports of water from LEO to the rest of cis-lunar space would probably be commercially non competitive. In fact, lunar sources of water might someday compete with water resources being exported to LEO from the surface of the Earth via the Phantom Express.

Notional crewed Orion-ACES reusable shuttle approaching EUS derived
propellant producing water depot @ NRO with 600 KWe solar array. The
notional WPD-OTV-125 would be capable of storing up to 200 tonnes of
water and up to 125 tonnes of LOX/LH2 water derived propellant.

Traveling
to the moon using a propellant producing water depot architecture could
be much easier and safer since vehicles returning from deep space would simply return to Earth orbit instead of plunging directly through the Earth's atmosphere to the Earth's surface. Commercial Crew launched vehicles could
simply launch astronauts or paying tourist to LEO to dock with a
commercial space station. A reusable ACES upper stage perhaps joined
with an Orion capsule with no Service Module would refuel at a nearby
propellant depot and then dock with the space station to pick up the
passengers from Earth. The Orion-ACES would then travel for about five
days to an orbiting commercial outpost located at NRO (Near Rectilinear
Lunar Orbit). A XEUS vehicle would refuel at a nearby propellant depot
and then dock at the deep space habitat to pick up the passengers. Less
than 12 hours would be required to transport the passengers to the
lunar surface and the XEUS would still have enough propellant to return
the crew back to the NRO habitat for the return trip to LEO and then
back to the Earth's surface.

The daily deployment of
water to LEO by the Phantom Express could allow other launch vehicles to
focus their efforts on deploying passengers and large and heavy
habitats, crewed interplanetary spacecraft, and other large structures
to LEO where they could easily be transported to other areas of
cis-lunar space and beyond by reusable orbital transfer vehicles such as
the future ACES or IVF modified EUS. Links and References

Monday, August 6, 2018

Because of the political inability to deal with the long term disposal of spent fuel from commercial nuclear reactors in the US by the federal government, some states in the US have banned the building of new commercial nuclear power plants.

California state law, for instance, has banned the construction of new commercial nuclear power plants until the US Federal government establishes a long-term policy on the disposal of spent fuel (nuclear waste). And with current plans to close its last nuclear power plant (Diablo Canyon) by the year 2025, California will eventually have no nuclear facilities providing carbon neutral electricity to its nearly 40 million residents.

While the US has principally focused on finding a permanent site for the spent fuel from its commercial nuclear facilities, some nations, such as France, have focused on recycling the plutonium component of spent fuel while storing away the fissile and fertile uranium for perhaps future use in commercial nuclear reactors-- plus the residual radioactive material that cannot be recycled

While France mixes plutonium with uranium 238 (MOX) to partially recycle nuclear waste in its current light water reactors, this process produces even more plutonium. But a Swedish company (Thor Energy) has come up with an alternative solution. They propose mixing the plutonium from spent fuel with fertile thorium instead of fertile uranium 238. The utilization of such fuel in conventional light water reactors would allow for the plutonium to be incinerated while producing electricity while producing fissile uranium 233 that could be eventually extracted and used to enrich the spent fuel containing fissile uranium 235 and fertile uranium 238 stored away. This would allow most spent fuel produced from nuclear reactors to be recycled to produce even more carbon neutral energy.

Thor Energy envisions using a mix of 90% thorium and 10% plutonium
in conventional light water reactors. Thorium Mox could also be used in
future underwater light water nuclear reactors such as France's
FlexBlue system. Remotely sited underwater reactors could be used to produce carbon neutral synfuels (methanol, gasoline, jet fuel, diesel fuel, etc.) which could be shipped to coastal towns and cities around the world for transportation and local heat and electricity production.

Monday, July 30, 2018

During NASA's Constellation program, the American space agency chose Boeing's Altair concept as the landing vehicle design to return American astronauts to the surface of the Moon. As a two staged (descent and ascent) crew landing vehicle and as a single stage cargo landing vehicle, the Altair was supposed to be housed in the large payload fairing of the Ares V super heavy lift rocket. But in 2010, the Constellation program was canceled by the Obama administration, a decision that became law in April of 2011. And this ended the development of Ares V and Altair lunar landing vehicle.

Notional Altair crew landing vehicle (Credit: NASA)

Notional Altair cargo landing vehicle (Credit: NASA)

A year later, Congress began funding a new heavy lift program, the Space Launch System (SLS), while continuing to fund the development of the Orion component of the Constellation program. While there has been no significant Congressional funding for a lunar landing vehicle, a large variety of a vehicle concepts have been proposed to return American astronauts and cargo back to the lunar surface by several space companies.

2.4 meter super lightweight cryotank (Credit: Boeing Aerospace)

Here, I propose another reusable extraterrestrial cargo and crew landing vehicle (the ELV-3) concept that would be much simpler than Boeing's Altair vehicle. The ELV-3 would be launched by the SLS and utilized to deploy very large and heavy cargo or crews to the lunar surface. And with the addition of a HIAD or an ADEPT deceleration shield, the ELV-3 could also deploy largo cargoes and crew to the surface of Mars.

Notional ELV-3 lunar lander display retractable panel

X-ray view of three tank configuration for ELV-3

View of ELV-3 radiator and side thrusters

Top x-ray view of ELV-3 and its three tank configuration

Technologically, the notional ELV-3 spacecraft proposed here would be a substantially simpler vehicle than Boeing's canceled Altair spacecraft. Instead of the Altair's descent vehicle's four liquid oxygen tanks accompanied by four liquid hydrogen tanks, the ELV-3 would have just two 2.4 meter in diameter hydrogen tanks plus one 2.4 meter in diameter liquid oxygen tank, all linear aligned within an octagonal shaped cruciform.

The problems associated with eight feedlines, differential tank pull due
to unuasable propellant, increased tank heating resulting from the
numerous tank penetrations, problems with pressure control during burns
and long coastal phases caused by the large number of tanks are
significantly reduced by reducing the cryotank numbers from eight down
to just three. Utilizing just three tanks also reduces the overall mass
of the tank weight.

Problems associated with the RL-10 exhaust plume just a few meters above
the lunar surface during landings could be alleviated by using side
thrusters positioned well above the surface. Additionally, the IVF (Integrated Vehicle Fluids) ullage gas fueled thrusters
could also be automatically extended outwards away from the side panels
(more than 8.4 meters in diameter) for exceptionally large payloads that
extend beyond the diameter of the octagonal panels.

While the deck of the ELV-3 would be approximately two meters higher
than the Altair, the ELV-3 would have the advantage of a substantial
amount of empty space on each side of the linear aligned propellant
tanks. Twin retractable wall panels on each side could accommodate a
rectangular cargo area at least 7.2 meters high by 2.2 meters by 2.8
meters.

Twin mobile lunar cranes stored within the ELV-3 side cargo areas with additional cargo located at the top central area

The large dimensions of the side cargo areas would also be able to
accommodate twin mobile lunar cranes with telescopic booms extending
well above the the top deck. Each electric powered crane would be
equipped with a cable hook for unloading large payloads and with cable
clamshells for digging up and redepositing lunar regolith. With each
mobile crane already weighing more than 12 tonnes, the deposition of
lunar regolith (weighing approximately 1.5 tonnes per square meter) into
the automatically expanded regolith bins of the other vehicle could
increase each crane's counter weight by more than 18 tonnes. This would
allow each mobile crane to be able to easily offload payloads on top of
the ELV-3 weighing nearly 30 tonnes. If devices are deployed to the
lunar surface to magnetically extract iron and other metallic dust from
the top ten centimeters of lunar regolith then the deposition of this
much heavy material into the regolith bins could easily increase the
counter weights of the mobile cranes by more than 100 tonnes.

Panel deployment of twin mobile lunar cranes

The deployment of such mobile lunar cranes could, of course, be used
to unload and transport payloads from a variety of other lunar landing
cargo space craft.

Notional electric powered mobile lunar crane

The clamshell crane could also be used
to deposit regolith within the surrounding walls of lunar habitats
providing the large multilevel pressurized habitats with appropriate
shielding against cosmic radiation (completely shielding the habitats
from the heavy nuclei component). Such regolith shielding could provide
the habitat with protection from micrometeorites and from the extreme
thermal fluctuations from the lunar environment.

Mobile lunar crane using its telescopic boom to lift a 20 tonne SLS propellant tank derived lunar habitat from the top of an ELV-3 cargo lander. The 20 tonne payload, of course, would weigh only one sixth as much on the lunar surface.

The cargo version of the ELV-3 could also be utilized to transport large and heavy payloads to the martian surface if HIAD or ADEPT deceleration shields are utilized along with mobile cranes with lifting capabilities not too dissimilar to vehicles deployed to the lunar surface.

Maximum additional cargo to and from the lunar surface if able to refuel on the lunar surface: 14 tonnes

Notional ELV-3 crew landing vehicle

As a crew vehicle, the ELV-3 would use three pressurized modules derived from Boeing's 2.4 meter in diameter tank technology. The centrally positioned module (passenger module) would be the heaviest since it would be internally heavily shielded to protect astronauts from the exceptionally deleterious heavy nuclei component of cosmic rays. This would add at least four tonnes of extra shielding weight to the passenger module relative to the similar sized command module and airlock on opposite sides of the passenger module. The passenger module would also serve as a storm shelter in case of a major solar event when the ELV-3 is moving through cis-lunar space.

Because of its weight and limited fuel (up to 31 tonnes of LOX/LH2 propellant), two vehicles would be required for round trip sortie missions
between NRO and the lunar surface. One ELV-3 would be used to transport the other ELV-3 and its crew to low lunar orbit while the crewed ELV-3 would land on the lunar surface and then return to lunar orbit after its mission where the orbiting ELV-3 would transport both vehicles back to NRO. So spacecraft such as the ULA's XEUS (up to 68 tonnes of LOX/LH2 propellant) and Lockheed Martin's MADV (80 tonnes of LOX/LH2 propellant) would be much more capable than the ELV-3 as a crew launch vehicle for sortie missions since only one vehicle is required for sortie missions originating from NRO.

However, once propellant producing depots
are deployed to the lunar surface, only one ELV-3 vehicle would be required to transport crews between the Earth-Moon Lagrange points and the lunar surface and back. Additionally, the crewed versions of the ELV-3 would have a major advantage by being able to transport both astronauts plus more than 14 tonnes of additional payload to and from the lunar surface when fully fueled.

After a side panel is deployed, astronauts ride an electric powered scissor lift down towards the lunar surface

If propellant producing water depots are deployed at LEO and NRO, the ELV-3 could also be used transport crews between LEO and NRO. This would provide NASA and private commercial space transportation companies with an alternate means from LEO to the Lagrange points.

Utilizing its side cargo areas, an unmanned ELV-3 could also be used to deploy a multitude of mobile robots
to the surfaces the Moon, the moons of Mars (Deimos and Phobos), to the
moons of Jupiter (Io, Ganymede, Europa, and Callisto), and even to the
surfaces of some of the the largest asteroids in the asteroid belt (Ceres,
Vesta, Pallas, etc.).

"The knowledge that we have now is but a fraction of the knowledge we must get, whether for peaceful use or for national defense. We must depend on intensive research to acquire the further knowledge we need ... These are truths that every scientist knows. They are truths that the American people need to understand." (Harry S. Truman 1948).